Diesel fuel composition



United States Patent 3,481,716 DIESEL FUEL COMPOSITION Adolph V. Mrstik,Chicago Heights, Walter F. Schoen,

South Holland, and Frederick L. Voelz, Orland Park,

111., assignors to Sinclair Research, Inc., New York,

N.Y., a corporation of Delaware No Drawing. Continuation of applicationSer. No. 723,555, Apr. 23, 1968. This application Jan. 23, 1969, Ser.No. 797,346

Int. Cl. C101 1/30, 1/14 U.S. Cl. 44-68 8 Claims ABSTRACT OF THEDISCLOSURE A diesel fuel composition for use in diesel engines adaptedto have substantially reduced combustion deposits formed in thecombustion chambers of the engine consisting essentially of a dieselhydrocarbon fuel and a diesel fuel-soluble metal salt of a phosphoruscompound which reduces deposit formation having the formula:

R0 R0 SH This application is a continuation of application Ser. No.723,555, filed Apr. 23, 1968, which, in turn, was a continuation-in-partof applications Ser. No. 418,917, filed Dec. 16, 1964 now abandoned andSer. No. 419,578, filed Dec. 18, 1964 now abandoned.

The present invention is directed to diesel fuel compositions havingreduced deposit-forming tendencies when burned in the presence ofcombustion air in the combustion chambers of compression-ignitionengines.

A common problem associated with compression-ignition engines such asdiesel engines is the excessive buildup of carbonaceous deposits in thecombustion chambers of these engines, particularly when the engines arerun under, idle or low load conditions, or when using the heavier dieselfuels such as the heavy straight run distillate fuel and straight rundistillates mixed with catalytically cracked distillate fuels orresidual fuels. These combustion chamber deposits interfere with normalflame propagation and cause loss of power and/0r inefficient engineoperation.

It has now been found that a diesel fuel-soluble atomic number 27 to 30metal salt of certain phosphorus compounds when added to hydrocarbondiesel fuels in small amounts reduces the amount of deposits formed inthe combustion chambers of engines wherein such fuels are burned. Thephosphorus compound, the atomic number 27 to 30 metal salts of whichconstitute the additives of the present invention, have the followingformulae:

R0 OH R0 SH and I II

"ice

an aliphatic, aromatic or mixed aliphatic-aromatic radical and ispreferably non-olefinic and non-acetylenic, i.e. having adjacent carbonatoms no closer than 1.40 A. The total number of carbon atoms in 'amolecule of the phosphorus compound is preferably up to about 30 or even40 and the metal salt of the phosphorus compound is soluble .in thediesel fuels at least to the extent employed in this invention. Thephosphorus compounds from which the metal salts, i.e. the cobalt,nickel, copper and Zinc salts, of the invention are made can be obtainedby any method known to the art as, for instance, by reacting aliphatic,including cycloaliphatic, alcohols or aromatic hydroxy compounds such asphenols and naphthols with P 0 to form phosphoric acid esters (I) andwith P S to form the dithiophosphoric acid esters II). Mixtures ofaliphatic or aromatic hydroxy compounds can be employed in the reactionif desired and the compounds may be substituted with nondeleteriousgroups and can be saturated or unsaturated in the alphatic, includingcycloaliphatic, chains. The preferred alcohols are alkanols, which canbe straight or branched chain, and alkyl substituted phenols whose alkylsubstituents contain a total of up to 18 carbon atoms, and preferablyare lower alkyl, especially methyl. Illustrative of suitable alcoholsare pentanol, butanol, octanol, isoctanol, 2- ethyl-heptanol, dodecanol,oleyl, octadecyl, tetradecyl alcohols, alcohols prepared by the 0x0process, phenol, and alkylated phenols such as cresol, xylenol, ethylphenol, diethyl phenol, propyl phenol, butyl phenol, dibutyl phenol,monoamyl phenol, diamyl phenol, octyl phenol, dioctyl phenol, decylphenol, dodecyl phenol, tetradecyl phenol, hexadecyl phenol andoctadecyl phenol.

The reaction of the alcohol and P 0 or P 8 to prepare the partial esterscan be conducted by heating the reactants at temperatures of from aboutC. to about C. for a period of time sufficient to effect substantiallycomplete reaction, usually about 1 to 15 hours. An inert solvent such astoluene, xylene or the like may be used to facilitate the reaction. Auseful molar ratio of alcohol to P 0 or P S is about 3:1.

The ester products can be monoalkyl, dialkyl, monoaryl, or diaryl estersof phosphoric acid or dithiophosphoric acid, or any combination thereof.The mixed esters are often present, for instance, in a mole ratio of atleast 25% of each, say about 60 to 40% monoester and 40 to 60% diester.The metal salt of the mixed esters can be prepared by directly reactingthe mixed esters with a carbonate or acetate of a metal having an atomicnumber of 27 to 30. Alternatively, the sodium salt of the mixed esterscan first be formed and then reacted with an aqueous or alcoholicsolution of a chloride of the metal to produce the corresponding dieselfuel-soluble, metal salt of the present invention.

The hydrocarbon diesel fuels of the present invention can be thestraight run distillate type diesel fuels or fuel blends containing inlarge part the straight run diesel fuels. Economy type fuels can be usedand usually represent blends of straight run and catalytically crackeddistillate stocks with the latter type frequently predominating. Otherdiesel fuels contemplated include residual oil stocks cut-back toappropriate viscosity levels by means of about 5% or more, usually about40 to 60% distillate cutter stock composed of straight run and/orcatalytically cracked components boiling in the diesel fuel range.

The amount of the additive of the invention incorporated into the dieselfuel may vary depending upon the specific type and grade of diesel fuelselected as well as the particular engine utilized, the power output atwhich the engine is run, etc., but will be suflicient to substantiallyreduce the combustion deposits formed in the combustion chambers of theengine. Generally, about 0.002 to 0.4 or even up to 0.8 millimole ormilligram atom of metal, preferably 0.025 to 0.3 millimole or milligramatom, as the metal salt per gallon of diesel fuel are utilized. Thisoften means that about 0.5 to 25 or 30 or more pounds of the metal saltis added, preferably about 4 to 10 pounds, per 1000 barrels of dieselfuel.

The following examples are included to further illustrate the invention.

EXAMPLE I A cobalt salt of mixed mono and diisodecyl phosphoric acid wasprepared as follows:

Two moles of mixed, approximately 50:50 monoand di-isodecyl esters ofphosphoric acid were reacted with a molar excess of cobaltous carbonate.The reaction was carried out at 75 C. for one hour. The reaction productwas filtered, water-washed several times and refiltered. The resultinghydrocarbon solubles were dried to a constant weight. Product analysesshowed 4.53 weight percent cobalt and 4.5 weight percent phosphorus.

The cobalt salt thus prepared was added to a petroleum diesel fuel inthe amount of 21.4 pounds of additive per thousand barrels of dieselfuel. The diesel fuel to which the cobalt additive was added had thefollowing inspections:

4 EXAMPLE II The nickel salt of mixed, approximately 50% monoandapproximately 50% di-cresyl esters of phosphoric acid was prepared byreacting 2 moles of the mixed monoand di-cresyl esters with an excess of2 moles of nickel carbonate at 8090 F. for 1 hour. (The esters werederived by reacting mixed cresols with P Upon completion of thereaction, the reaction mixture was filtered. The hydrocarbon solubleswere water-washed several times, refiltered and the resulting nickelsalt of mixed monoand di-cresyl esters of phosphoric acid was dried toconstant weight. Elemental analysis of the additive showed: nickel 2.8%;phosphorus 2.7%.

Substantially the same results obtained by the cobalt salt in Example Iabove can also be obtained by adding 21.5 lbs. amounts of thethus-prepared nickel salt 'of mixed monoand di-cresyl esters ofphosphoric acid per 1000 barrels of the diesel fuel of Example I.

EXAMPLE III The nickel salt of hexyldithiophosphoric acid ester wasprepared as follows:

Four moles of hexanol were reacted with one mole P 8 to form mixedmonoand di-hexyldithiophosphoric acid ester. A slight excess over onemole of nickel carbonate was reacted with each mole of the ester to formA I i 30.6 the nickel salt. The reactions were carried out at 80 C.Flash, PM, F 184 With the resulting product being filtered,water-Washed, Viscosity at 100 F., SUS 37.97 hydrocarbon-washed(benzene), then dried at 80 C. to Pour, F B-l0 30 constant weight.Sulfur, wt. percent 0.40 The addition of 21.4 lbs/1 000 barrels of thethus-pre- Ash, percent 0.0002 pared nickel salt to a diesel fuel havingan API gravity of Cetane No. 40.5 30.6, a Cetane No. of 40.5 and havinga distillation range IBP, F. 382 f P 382 to EP 676 F., provides acomposition hav- 10% evap., F 420 g reduced combustion deposit-formingtendencies. 50% evap., F 506 Diesel fuel compositions having similarcharacteristics 90% evap., F 612 can be obtained by adding to the dieselfuel of Example End point, F. 676 III the following additives in thedesignated amounts:

Additive #li iit l tl Cobalt salt of oetadecyldithiophosphorie acid"Copper salt of didodecyldithiophosphoric acid 20 VI Zn salt ofdieicosyldithiophosphotic acid 22 The above fuel, without the cobaltorganophosphate, was run in a GM Model 2-71 two stroke cycle dieselengine. The engine was run for hours at a constant speed, idlecondition. After this test the head was removed and the deposits in thecombustion chamber were examined. The deposits were tightly bound to thehead, and weighed 2.5920 grams.

The engine was thoroughly cleaned, and a second test run was made on thesame diesel fuel plus 21.4 pounds per 1000 barrels of the cobaltorganophosphate. After 45 hours of constant speed, idle operation, thehead of the engine was again removed and the deposits examined. Thistime the bonding between the head and the deposits Was loose, and thetotal deposit accumulated on the head was only 2.3615 grams, a reductionof 8.9 percent from the previous run.

The engine was again cleaned and reassembled, and the base fuelcontaining no additive was run for 45 hours at an idle condition,followed by a one-hour operation at full load. The engine was cleanedand the same cycle repeated with the fuel containing 21.4 pounds per1000 barrels of the cobalt additive. Total deposit weight col lected onthe head was 0.2545 gram without the additive, and 0.1387 gram with theadditive, or a reduction of 45 percent as a result of the cobaltadditive.

These four test runs show that the metal salts of the invention, whenadded in very low concentrations to diesel fuel, will reduce depositsaccumulated in the combustion chambers of diesel engines.

on R0 SH wherein R is a hydrocarbon radical of up to about 30 carbonatoms on the average, and R is selected from the group consisting ofhydrogen and R, said metal having an atomic number of 27 to 30 and beingpresent in an amount sutficient to provide about 0.002 to 0.8 milligramatoms of metal per gallon of diesel fuel.

2. The composition of claim 1 wherein the amount of said metal is about0.025 to 0.3 milligram atoms of metal per gallon of diesel fuel.

3. The composition of claim 1 wherein the metal salt is the cobalt saltof mixed monoand di-isodecyl esters of phosphoric acid.

4. The composition of claim 1 wherein the metal salt is the cobalt saltof mixed monoand di-isodecyl esters of dithiqph qsphoric acid.

6 5. The composition of claim 1 wherein the metal salt and the amount ofsaid metal salt is about 0.025 to 0.3 is a salt of a phosphorus compoundhaving the formula: milligram atoms of metal salt per gallon of dieselfuel.

8. The composition of claim 7 wherein the metal salt is the cobalt, saltof mixed monoand di-isodecyl esters 5 of dithiophosphoric acid.

O 0 References Cited and the amount of said metal salt is about 0.025 to0.3 UNITED STATES PATENTS milligram atoms of metal salt per gallon ofdiesel fuel.

6. The composition of claim 5 wherein the metal salt 215 60542 7/1951Bartleson et a1 44-68 is the cobalt salt of mixed monoand di-isodecylesters 10 3,055,748 9/1962 Harfle 44 '69 ofphosphoric acid 3,055,9259/1962 Hartle 44-69 7. The composition of claim 1 wherein the metal saltis 3,065,065 1/1962 Sutton et 44 69 a salt of a thiophosphorus compoundhaving the formula: V DANIEL E. WYMAN, Primary Examiner 0 R SH Y. H.SMITH, Assistant Examiner US. Cl. X.R.

